Browsing by Author "McCabe, Lauren"
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Item Inverse Designed Couplers for Use in Gallium Arsenide Photonics(ACS Photonics, 2023-05-17) Carfagno, Henry; Guidry, Melissa A.; Yang, Joshua; McCabe, Lauren; Zide, Joshua M. O.; Vučković, Jelena; Doty, Matthew F.Highly efficient photonic couplers are a necessary component of a scalable platform to couple quantum emitters into quantum fiber networks. We inverse-designed couplers for use in gallium arsenide membrane-based photonics that are compatible with indium arsenide quantum dots, one of the highest quality quantum light sources available. We fabricated and tested at least 4 instances of devices following 11 different designs. All inverse-designed structures outperformed the traditional grating outcoupler in a single-mode optical fiber optical setup. Using a novel sleeve and bulk fabrication method allowed for a smaller allowable minimum feature size constraint in the inverse design optimization protocol. Employing this new design constraint improved the average device transmission efficiency from 17.4% to 27.5%. The use of broadband optimization criteria did not result in statically significant improvement in actual bandwidth, but did decrease the variance in the measured bandwidth, suggesting a more robust design.Item A sleeve and bulk method for fabrication of photonic structures with features on multiple length scales(Nanotechnology, 2022-09-21) Carfagno, Henry; McCabe, Lauren; Zide, Joshua; Doty, Matthew F.Traditional photonic structures such as photonic crystals utilize a) large arrays of small features with the same size and pitch and b) a small number of larger features such as diffraction outcouplers. In conventional nanofabrication, separate lithography and etch steps are used for small and large features in order to employ process parameters that lead to optimal pattern transfer and side-wall profiles for each feature-size category, thereby overcoming challenges associated with RIE lag. This approach cannot be scaled to more complex photonic structures such as those emerging from inverse design protocols. Those structures include features with a large range of sizes such that no distinction between small and large can be made. We develop a sleeve and bulk etch protocol that can be employed to simultaneously pattern features over a wide range of sizes while preserving the desired pattern transfer fidelity and sidewall profiles. This approach reduces the time required to develop a robust process flow, simplifies the fabrication of devices with wider ranges of feature sizes, and enables the fabrication of devices with increasingly complex structure.